SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
Communications backdoors add a message to an existing communications port already used in the application. Typically this is the PMBus interface, but it could be any communications interface.
The standard TI firmware generally supports a simple communications backdoor with a PMBus D9 command used to clear the flash checksum. For added security, this could be changed so that it erases the flash instead. The command code could be changed. In addition, more bytes could be added to the command sequence, requiring a multi-byte checksum for flash changes.
The serial port could also be used in a similar way.
Advantages:
Disadvantages: